Steven P. Ferraro

Temporal changes in the benthos along a pollution gradient: Discriminating the effect of natural phenomena from sewage-industrial wastewater effects

Abstract As pollution from the Los Angeles County Sanitation Districts (LACSD) outfalls decreased between 1980 and 1983, the macrobenthic community partially recovered and surficial (0–2 cm deep) sediment contamination and toxicity decreased at 60 m water depth along a pollution gradient from the outfalls. Pollution from the LACSD outfalls continued to decrease but macrobenthic conditions and surficial sediment quality deteriorated 1 km, was unchanged 3 km, and improved 5–15 km from the LACSD outfalls between 1983 and 1986. The net effect of natural phenomena is indicated when ecosystem changes occur in the opposite direction from that expected under prevailing pollution conditions. Our data suggest that the net effect of natural phenomena (e.g. winter storms, El Nino) on the benthos was greater than LACSD wastewater effects 1 km, about equal to LACSD wastewater effects 3 km, and less than the LACSD wastewater effects 5–15 km from the outfalls at the LACSD 1983–1986 mass emission rate. Surficial sediment samples collected beyond the 1 km station from the LACSD outfalls probably represented ⪢ 3 years of natural + effluent particulates accumulation, and they were, therefore, better suited for detecting long-term trends than for testing short-term temporal variability in surficial sediment contamination and toxicity. Nevertheless, some contaminants in the surficial sediments significantly increased between 1983 and 1986, probably primarily reflecting renewed wastewater effects near the outfalls and the effects of natural phenomena (e.g. storm-induced sediment transport or erosion) further from the outfalls. Since natural phenomena may have an effect on the benthos ≥ 3 years of LACSD wastewater effects, short-term benthic changes must be interpreted cautiously at the study site.

Predicting bioaccumulation potential: A test of a fugacity-based model

Clams (Macoma nasuta) from an unpolluted site in Yaquina Bay, Oregon were exposed in the laboratory for 28 days to 6 field-contaminated sediments (treatments) which varied widely in concentration of 10 organic pollutants. Mean accumulation factors (AF = (concentration in tissue/lipid, %/100)/(concentration in sediment/total organic carbon, %/100)) of 8 neutral organic compounds (DDE [p,p′], 2,2′,3,5′6-pentachlorobiphenyl, 2,3′,4,4′,5-pentachlorobiphenyl, Aroclor® 1254, pyrene, chrysene, benzo[a]pyrene, benzo[b,(k)]fluoranthene) were homogeneous across treatments. Statistically significant differences were detected between some treatment AFs for ODD [p,p′] and benz[a]anthracene, and between some chemicals within treatments (experimentwise a=0.05). Accumulation factors were less than 2 and less variable in highly polluted, organically enriched sediments (total organic carbon > 3.69 ± 0.044%), but sometimes exceeded 2 in clams exposed to surficial (0–2 cm deep) sediments with low pollutant concentration and low organic carbon content (⩽ 0.86 ±0.037%). These results suggest that the AF model may provide reasonable estimates of bioaccumulation potential of hydrophobic neutral organic compounds in organically enriched, polluted sediments.

A comparison of methods for collecting interstitial water for trace organic compounds and metals analyses

Abstract Several common materials and methods used to collect interstitial water (IW) were evaluated to determine their effect on the accuracy and precision of measured concentrations of selected organic compounds and metals. We compared the concentration of pollutants in dosed seawater before and after exposure to stainless steel and Teflon centrifuge tubes, glass fiber and Nuclepore filters, cellulose dialysis membranes and fritted glass tubes. Exposure to most hardware materials did not significantly affect the concentration of four metals (Cd, Cr, Cu, Pb) but there was significant loss (up to 79%) of two organic compounds (fluoranthene, p,p′-DDE) to almost all the hardware materials tested. Of five commonly used IW collection methods (centrifuging, centrifugal drainage or basal cup, squeezing, vacuum filtration and dialysis) investigated, the centrifuge method was judged the most accurate and precise for polycyclic aromatic hydrocarbons and PCBs. All IW collection methods tested showed high variability for the metals. As a result, with one exception (Cu), there was no significant difference detected in the accuracy of the methods for metals.

Optimal benthic macrofaunal sampling protocol for detecting differences among four habitats in Willapa Bay, Washington, USA

As part of an effort to estimate estuarine habitat values with respect to ecological indicators of benthic macrofaunal community condition, an optimal (effective and least costly) sampling protocol (sample unit size [area x depth], sieve mesh size, and sample number [n]) was determined. The goal was to use four ecological indicators (number of species, abundance, biomass, and fish and crab prey abundance) to detect differences among four intertidal habitats in Willapa Bay, Washington, United States. The four habitats were eelgrass (Zostera marina), Atlantic cordgrass (Spartina alterniflora), mud shrimp (Upogebia pugettensis), and ghost shrimp (Neotrypaea californiensis). Four sample unit areas (0.005, 0.010, 0.015, and 0.020 m2), two sample unit depths (0–5 and 0–10 cm), and two sieve mesh sizes (1.0 and 0.5 mm) were evaluated. The optimal sampling protocol was defined as the least costly protocol capable of reliably (statistical power, 1−β≥0.80) detecting significant (α=0.05) differences among ≥4 of the 6 pairwise habitat contrasts by ANOVA on all four ecological indicators. The relative cost of each sampling protocol was estimated as a direct function of the sample unit size and number and the cost-in-processing-time ratios of 1 (5 cm deep):1.7 (10 cm deep) and 1 (≥1.0 mm macrofauna size fraction); 2.5 (≥0.5 mm macrofauna size fraction), which were taken from previous studies. The optimal sampling protocol was 15–20, 0.01-m2×5-cm deep, 0.5-mm mesh samples per habitat.

Optimum macrobenthic sampling protocol for detecting pollution impacts in the southern California bight

The optimum macrobenthic sampling protocol [sampling unit, sieve mesh size, and sample size (n)] was determined for detecting ecologically important pollution impacts in the Southern California Bight, U.S.A. Cost, in laboratory processing time, was determined for samples obtained using fourteen sampling units (0.005–0.1 m2 surface area) and two sieve mesh sizes (1.0 and 0.5 mm). Statistical power analyses for t-tests of means were performed to estimate the minimum sample size (nmin) needed to reliably (α=0.05, 1−β≧0.95) reject the null hypothesis of no difference between a reference and both a stimulated and a degraded station on twelve measures of community structure. The optimum sampling protocol for detecting impacts was determined as that with the lowest total cost ×nmin on most measures.Five replicate, 0.02 m2×5 cm deep, 1.0 mm mesh samples per station could reliably distinguish reference from impacted conditions on nine or ten measures of community structure at less than one quarter of the cost of the standard sampling protocol of 5 replicate, 0.1 m2, 1.0 mm mesh samples per station. About 5 replicate, small (<0.1 m2), 1.0 mm mesh samples per station may often be optimal for detecting important structural changes in macrobenthic communities with naturally high species richness and abundance.

Accumulation factors for eleven polychlorinated biphenyl congeners

According to the fugacity approach pollutant uptake by an organism is determined by the chemical fugacity differential between the organism and its environment. The Accumulation Factor (AF) is a simple, fugacity-based model which has been shown to be useful for predicting the bioaccumulation potential of hydrophobic neutral organic compounds in sediment dwelling animals. Previously, the constancy of AFs for ten hydrophobic neutral organic compounds were tested by exposing clams (Macoma nasuta) in the laboratory for 28 days to six field-collected sediments varying widely in C{sub S}, TOC, and other chemical and physical characteristics. Sediment and tissue samples from that study were achieved and later analyzed for 11 polychlorinated biphenyl (PCB) congeners. In this paper the authors report mean and maximum AFs (AF{sub max}) for 11 PCB congeners and test the constancy of the AFs across 5 sediments (treatments) by congener and across the 11 congeners by treatment.

Selected chemical contaminants in surface sediments of Commencement Bay and the tacoma Waterways, Washington, USA

Abstract Eight metals, 21 organic priority pollutants, and 11 other contaminants and contaminant-related sediment characteristics were measured in surface sediments (upper 2 cm) at 21 locations in Commencement Bay and the Tacoma Waterways, Washington. Summary statistics were calculated and statistical approaches (analysis of variance, multiple comparisons tests, cluster analysis and principal component analysis) were applied to subsets of the data to classify sediment contamination. Overall sediment contamination was highest in the Sitcum, City and Hylebos Waterways, intermediate in Commencement Bay, at the entrances to the Tacoma Waterways and in the outer reaches of the Blair and Hylebos Waterways, and lowest at the Blair Waterway turning basin, the mouth of the Puyallup River and at a reference site near Browns Point. High concentrations of some contaminants appeared to be related to proximity to sources of contaminants. Depositional vectors, and chemical adsorption processes may also influence the spatial distribution of sediment contamination in the study area. Results of simple and partial correlation analyses indicate that arsenic, iron and manganese may be more closely associated with the clay fraction, while cadmium, copper and polynuclear aromatic hydrocarbons may be more closely associated with the total organic carbon content of sediments. We were unable to discriminate statistically between the affinity of chromium, lead, zinc and phthalates with the % clay or the total organic carbon content of sediments.

Ecological periodic tables for nekton usage of four US Pacific Northwest estuarine habitats

We compared the species composition and abundance of the total nekton community, using the Bray–Curtis similarity coefficient, and mean total nekton, fish and crab species richness, abundance and biomass, and shrimp abundance across four intertidal habitats in a US Pacific Northwest estuary: (i) eelgrass (Zostera marina); (ii) burrowing mud shrimp (Upogebia pugettensis); (iii) burrowing ghost shrimp (Neotrypaea californiensis); and (iv) unvegetated sand. Field sampling was conducted during daytime high tides, and was quantitative, stratified-by-habitat, randomized, and estuary-wide. More than 10 000 nekton specimens belonging to 64 taxa were collected in 454 samples during 10 sampling periods, each approximately one-month-long (from June to November), over 3 years (1998–2000). Non-metric multidimensional scaling analyses revealed annually recurring across-habitat patterns in total nekton Bray–Curtis similarity. Two-way (habitat, year) analyses of variance revealed annually recurring across-habitat pattern...